34 Vitality and Organization of Protoplasm. 



a contractil substance. But the reverse is really the case. The living 

 substance is pre-eminently an exp^ansil substaiice. Its contraction forms . 

 essentially part of the negative phase of vital motility, due to functional 

 dis'integration. Expansion, on the contrary, forms part of its positive 

 phase, due to functional reintegration. You irritate or stimulate an 

 amoeba sufficiently, and it contracts into a globule. You leave it then 

 to its own resources, and it re-expands, pushing forth one or more pseu- 

 dopodia. The intrinsic tendency of protoplasm is forcibly to expand or 

 spread out during functional restitution. The formative expansion of a 

 protoplasmic pseudopodium is the visible manifestation of the cumula- 

 tive reintegration of the functionally deteriorated substance of the body 

 from which it issues. 



Pseudopodia during their outflow assume a more or less elongated 

 shape, because on contact with the medium the substance of the surface 

 solidifies and forms an envelope confining the flow of the expanding 

 substance, which is seen to continue within the envelope or tube. This 

 more or less rigid envelope is occasionally ruptured by an all too forcible 

 inroad of new expanding substance, whereupon an additional pseudo- 

 podium issues from the ruptured spot, forming a side branch, and giving 

 rise to complex phenomena of vital motility. 



The real consistency of flowing protoplasm has been a great puzzle to 

 investigators. It could not be considered a real fluid, nor a real viscid, 

 nor a real celloid. For the manifold phenomena of its vital motility 

 refused to be explained by any property possessed by these different 

 states of material consistency. The progressive reintegration of the 

 substance which forms the pseudopodia is evidently that which gives 

 rise to its apparent outflow. This apparent outflow is produced, not by 

 anything resembling the flow of a genuine fluid, but by the progressive 

 expansion of protoplasm during its cumulative reintegration. What 

 takes place here is an eminently active and vital formative process, and 

 no mere passive outspreading of any fluid or viscid substance. Nor is it 

 caused by any mode of inhibition. I know well the astonishing forma- 

 tion of beautiful, flexible, winding, tube-like shapes, which shoot out of 

 amorphous myeline when water is added to it.* But the formation of 

 pseudopodia is entirely due to a process of cumulative chemical reinte- 

 gration on the part of the living substance. 



That the apparent outflow of pseudopodia consists really in a cumu- 

 lative chemical elaboration of protoplasm can on close examination be 

 clearly detected in suitable specimens. At first only densely and coarsely 

 granulated substance issues from the protoplasmic individual. ' During 

 its apparent flow the substance is seen to become progressively finer gran- 

 ulated, and finally a completely hyaline substance, the so-called exto- 

 plasm, issues as cumulating result of the chemical reintegration. In 



*I have much experimented with the wonderful formative capacity of nye- 

 line, and have succeeded in imitating with it ahiiost all forms of natural and 

 morbid cells. The results were communicated in a paper read before the Royal 

 X Society of London, December 20, 18GG. 



